I would sugjest the sky and or wallace river. I was there on the christmas eve and found i just about about had the river to myself with all the people wanting to get home for christmas me I would rather fish. I had one for about a grand total of 5 seconds and saw one caught then bonked. Saw lots of fish rolling where the wallace meets the sky.
Try the Snoqualmie River along the David Powell road. Caught an 8lb hen last Tuesday and counted 8 steelhead in holding water immediately below the tokul creek fish hatchery on Friday. I've found the first two hours after dawn and the last hour before sunset to be the most productive.
Unfortunately, this stretch of water is quite crowded on the weekends - Lots of drift boats right now. If you can, try to get out on a weekday.